First prototype Nord 1500 Griffon canard (tail-first) delta-wing, missile-armed intercepter. The power unit is a S.N.E.C.M.A. Atar 101E.
THE GALTIER DELTA FAMILY . .
jet fighter, designed for a Nene or Tay fed by lateral intakes. Bothwere shoulder-wing aeroplanes at a time when the low wing was
almost universal. Unfortunately, the Arsenal lacked an experi-enced jet pilot for the VG-70, so that little flying was done on it;
and both flying prototypes of the VG-90 were lost, one throughcontrol-booster failure and the other due to the undercarriage
uplock releasing during a fast, high-g manoeuvre.
M. Galtier's next venture followed an equally novel aero-dynamic line. Asked to devise a short-range intercepter com-
bining rapid climb with high speed, he adopted a delta layout asthe best solution for obtaining sufficient wing area for climb and
manoeuvrability with the necessary low thickness/chord ratio todelay compressibility-drag-rise and yet give sufficient structural
depth for stiffness. Having decided on a delta for compactness,M. Galtier went further in this direction and virtually designed
the aeroplane round a straight-through duct for a S.N.E.C.M.A.Atar turbojet, with the load-carrying part of the fuselage added as a
superstructure. The use of elevators and ailerons on the wingtrailing edge in addition to a trimming tailplane is an unusual,
and apparently highly successful, combination.
M. Galtier is a very retiring individual and one given to long andcareful thought around a subject. He conveys the impression of
being extremely objective and careful to a degree. The Gerfautprogramme was based, therefore, upon full-scale glider testing as
well as upon normal wind-tunnel work, and so a wooden glider,the Ars.1301, was built (actually, it was originally made for a
supersonic rocket-fighter project, the Ars.2301, which was aban-doned). For the Gerfaut programme the glider's swept wing was
replaced by a delta, flown both with and without a trim plane.
The design and construction of the Gerfaut, which was a com-plete break with all M. Galtier's previous work, was remarkably
rapid; design started in September 1952, the prototype was com-pleted on September 26th, 1953, the first taxying trials were made
on October 20th, and the first flight on January 15th, 1954. OnAugust 3rd Mach 1 was exceeded in level flight without after-
burning—the first occasion on which this was accomplished.
The key factor in the high performance of the Gerfaut is cer-tainly the straight-through engine duct, which is truly circular
from nose to tail. This allows the Atar 101D to develop its fullthrust of 2,800 kg (6,200 lb) with minimum duct losses. The
moderate gross weight of the Gerfaut, at 4,750 kg (10,470 lb),results in a low thrust loading. One curious fact is that construc-
tion was pressed on so rapidly that the "high-speed" wing, with aspan of 6.5 m (21.4ft) and area of 19 sq m (204 sq ft), was finished
before a "low-speed" one of 7.5 m (24.6ft) span and 26.2 sq m(282 sq ft) area. The original intention was for the pilot to gain
experience with the larger wing and then to fit the small one forhigh speed. However, fortified by some hours of practice on the
Avro 707C at Boscombe Down, the S.F.E.C.M.A.S. chief pilot,M. Andre Turcat, carried out all the initial trials with the
small wing.
Both the smaller and larger wings have a sweep of 57i deg anda thickness of 5i per cent, so that their wave-drag characteristics
are similar. Despite the greater frontal area the Gerfaut remainsa level-supersonic aeroplane without afterburning, although the
engine is now so equipped. With the larger wing go medium-,instead of high-pressure, tyres and greater operational flexibility.
The superstructure cockpit and V-windshield confer a profilesimilar to that of some of the fast American types. The "sweep"
(Left) View from above of the air-intake duct, with the cockpit-floor support structure. At the top of the picture can be seen the intake lip
of the Atar and above it the fuel tank platform, with mounting for an immersed pump. (Centre) The pressure cockpit, which, built separately
as a superstructure, is mounted on top of the engine duct. The Gerfaut was one of the first aeroplanes to have a raked knife-edge windscreen.
(Right) The fairing behind the cockpit also forms the fuel tank. In addition to the access holes, a filler cap, contents-gauge unit, venting and
pressurizing pipes can be seen.